Low-cost passive radio frequency identification (RFID) tags are expected to be used in the future to identify and track various items, including consumer products. A typical passive RFID tag includes a thin, flexible substrate to which is applied an RFID integrated circuit (or chip) and radio frequency (RF) antenna. The RF antenna is coupled to the RFID chip and enables communication between the RFID chip and a remote RFID reading device. The tags usually include an attachment means—typically a layer of pressure-sensitive adhesive—to attach the tag to an item. The RFID chip incorporates an electronic memory that typically stores a unique chip identification code and may also have additional storage capability for other data.
RFID technology provides several key advantages over existing automated identification technologies (such as barcode technology), including:                the ability to read an RFID tag from a distance without requiring line-of-sight access to the tag;        the ability to read multiple RFID tags at high speed;        (depending on the type of RFID chip) the ability to write information to an RFID tag.        
An issue that has arisen regarding the use of RFID tags on consumer goods is the privacy of the consumer. One concern is that it may be possible for an RFID tag on a tagged item to be read after the item has been purchased and without the consumer being aware that reading of the tag has occurred. This may violate the privacy rights of consumers by allowing their shopping habits, movements, or product usage habits to be monitored.
One solution is to destroy or permanently disable the RFID tag after purchase of the tagged consumer item. While this would resolve the privacy concerns, it would have the disadvantage that if the consumer item is returned the store will no longer be able to use the RFID tag to identify it.
Other solutions have been proposed, in which the RFID performance of the tag can be permanently degraded after the tagged item is purchased, such that the RFID tag can still be read but only from a very short distance, thereby practically speaking preventing any tracking of a tagged item after the tag has been so modified. While this type of solution would resolve the privacy concern, and would allow returned items to be identified by means of the RFID tag, it would have the disadvantage that returned items could not be further processed through a retailer's RFID system due to the limited read distance of the modified tag, and so the returned item would in all probability need to be retagged.
A further disadvantage of using standard RFID tags to identify consumer products is that standard RFID tags do not incorporate any physical security features and so can easily be transferred from one item to another without their RFID function being affected. Consequently, after purchase of an item its RFID tag may be transferred to another item that is then brought back to the retailer as a product return. If the RFID tag is used to identify the returned item the store may issue a credit against the wrong item.